A river in Essex has been confirmed to contain a strain of herpes known to destroy shellfish populations.
An outbreak of the virus in the River Roach was confirmed by the Centre for Environment, Fisheries and Aquaculture Science (Cefas) and restrictions on the movement of Pacific oysters (for which there are several farms on the river) have been implemented.
Other nearby tributaries, the River Crouch, River Colne, and River Blackwater have also had controls imposed on them in response to the outbreak.
The Fish Health Inspectorate, the public body responsible for controlling situations such as this, must be consulted by anyone wishing to move oysters out of the restricted area.
Whilst the virus does not affect humans, the damage to the shellfish populations can be significant. An outbreak in Kent in 2010 resulted in the deaths of around 8 million oysters.
According to experts, the disease mainly affects juveniles, killing around 60-100%, and around 10-30% of adults.